ΔE 17.6, loose: different enough that you should pick on purpose. T'au Light Ochre is noticeably darker, more saturated than Light DAK Sand.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). T'au Light Ochre is noticeably darker, more saturated than Light DAK Sand.
The same difference applies the other way round: Light DAK Sand is noticeably lighter, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Light DAK Sand on the colour wheel See T'au Light Ochre on the colour wheel
All matches: Light DAK Sand equivalents · T'au Light Ochre equivalents